Originally posted by Slvr 540S:
The reason that the drivers seat doesn't originally move back as far as the passenger seat is due to the fact that in Europe the Steering wheel is on the other side and when the car is shipped to the states they install this peice that prevents the seat from moving to far from the wheel.
Hate to disappoint you, but only the Englishmen drive on the wrong side of the road, so this explanation is a bit... funny
Best guess for this blocker to be there is that it prevents the seat sliding too far back when someone fiddles with the seat while driving: if your seat suddenly goes too far back, you won't be able to reach the pedals.
Just my .02 mk